One of the important characteristics of a comforter, both for appearance and for comfort, is what is known as "loft". Loft refers to the thickness of the comforter, i.e. the height of the comforter, from the lower layer to the upper layer thereof. Typically, loft is increased by adding additional down to the comforter, giving it a desirable, puffy appearance. The quality and type of down are also factors in loft.
Typical comforter construction includes particular stitching patterns which join the upper and lower cover layers of the comforter, creating channels to hinder migration of the down. This is typically an important aspect of comforter construction. The stitching pattern, however, can decrease the appearance of loft, as the areas between the lines of stitching will appear as rolls or humps with the loft reaching a peak at a midpoint between adjacent stitching lines, instead of a high loft across the entire distance between the lines. A puffy or high loft appearance is thus difficult to obtain with conventional stitching or channeling patterns.
Hence, it is desirable for a comforter to have a puffy or high loft appearance, while also having stitching patterns which effectively prevent migration of the down.